This invention relates to the evaluation or testing of various substances placed in small cylindrical containers, sometimes called cuvets. Such containers are well known in the medical and biological field, and are frequently made of glass tubes of such small diameter that a liquid to be tested is drawn into the tube by capillary action. A typical material frequently tested is blood. The evaluation tests to be made on blood or other substances frequently include the separation of the ingredients or components of the liquid being tested, by subjecting the liquid to centrifugal force, and a subsequent measurement of the separated components.
A basic structure for performing such tests or centrifugal separation procedures comprises a rotor having radial grooves or recesses for receiving the sample containers, with resilient abutments at the outer ends of the containers, and with axially movable clamping means located centrally of the rotor, for receiving the inner ends of the containers. When the clamping means is moved axially to its loading position and the sample containers are placed in the apparatus, the containers are initially inclined upwardly from their outer ends toward their inner ends. Then the clamping member on which the inner ends of the containers rest is moved axially downwardly, to carry the inner ends of the containers downwardly to a straight line position and a little beyond the straight line position; in other words, to carry the inner ends down to the transverse plane (perpendicular to the axis of rotation of the rotor) which contains the outer ends of the containers, and a little beyond such plane, until the containers have a slight downward slope or inclination from their outer ends to their inner ends. Similarly to the action of straightening a toggle, this motion pushes the sample containers slightly radially outwardly into the resilient abutments at their outer ends, thus firmly sealing the outer ends of the respective containers, and at the same time holding them firmly in place for the subsequent high speed rotation of the rotor, to apply the desired centrifugal force to the contents of the containers.
The basic structure for accomplishing this is disclosed in the copending U.S. patent application of Wolfgang Konig, entitled "Apparatus for centrifugal separation and measurement of samples," Ser. No. 732,218 filed Oct. 14, 1976. The present invention is an improvement on the basic apparatus invented by Konig, the improvement relating to various details of the construction of the clamping means, including the provision of a spring tending to move a clamping member axially from clamped position to unclamped or loading position, and a latch for holding the clamping member in its clamping position until the latch is released.
An object of the present invention is to improve the basic Konig structure by providing a better and more easily operated clamping means, more easily and quickly operable by the user, and having greater certainty of remaining in clamped position during high speed rotation of the parts, eliminating any possibility of accidental movement from clamped position to unclamped or loading position.
This object is well fulfilled by apparatus according to the construction herein disclosed as an example of a preferred embodiment of the invention.